The characterization and ballistic evaluation of mild steel (original) (raw)
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An experimental study on the deformation and fracture modes of steel projectiles during impact
2013
Previous investigations of the penetration and perforation of high-strength steel plates struck by hardened steel projectiles have shown that under certain test conditions the projectile may fracture or even fragment upon impact. Simulations without an accurate failure description for the projectile material will then predict perforation of the target instead of fragmentation of the projectile, and thus underestimate the ballistic limit velocity of the target plate. This paper presents an experimental investigation of the various deformation and fracture modes that may occur in steel projectiles during impact. This is studied by conducting Taylor bar impact tests using 20 mm diameter, 80 mm long, tool steel projectiles with three different hardness values (HRC 19, 40 and 52). A gas gun was used to fire the projectiles into a rigid wall at impact velocities ranging from 100-350 m/s, and the deformation and fracture processes were captured by a high-speed video camera. From the tests, several different deformation and fracture modes were registered for each hardness value. To investigate the influence of material on the deformation and fracture modes, several series of tensile tests on smooth axisymmetric specimens were carried out to characterise the mechanical properties of the three materials. To gain a deeper understanding of the various processes causing fracture and fragmentation during impact, a metallurgical investigation was conducted. The fracture surfaces of the failed projectiles of different hardness were investigated, and the microstructure was studied for each hardness value.
Ballistic resistance of mild steel plates of various thicknesses against 7.62 AP projectiles
International Journal of Protective Structures, 2017
The ballistic resistance of mild steel plates has been studied against 7.62 AP projectiles through numerical simulations using ABAQUS/Explicit commercial finite element package. The projectiles were impacted on 4.7, 6, 10, 12, 16, 20 and 25 mm thick target plates at varying incidence angles. The material parameters proposed by authors for the Johnson–Cook model were used to predict the material behavior of target, while the material behavior of projectile was incorporated from the available literature. The numerical results thus obtained have been compared with the experiments available in the literature. The experimental and numerical results with respect to failure mechanism, residual projectile velocity, and maximum angle for perforation and the effect of configurations on spacing and critical angle of ricochet have been compared. A close correlation between the experimental findings and the predicted results has been found. In general, the resistance of target has been found to increase with an increase in target obliquity. The critical angle of the projectile ricochet has been found to decrease with an increase in target thickness. The ballistic limit for all given thicknesses of mild steel targets has also been obtained numerically. The ballistic limit thus obtained has been used to calibrate the Recht–Ipson empirical model for calculating the residual projectile velocity corresponding to a given incidence velocity. Simulations were also done for three-layered target of 4.7-and 6-mm-thick plate and spacing was varied to study its effect on their ballistic resistance. The variation of spacing at normal impact was found to have an influence as long as the spacing was smaller than the projectile length.
Experimental and Numerical Studies on Mild Steel Plates against 7.62 API Projectiles
Procedia Engineering, 2017
The ballistic resistance of 12 mm thick mild steel plates has been studied against 7.62 API projectiles through numerical simulations carried out using ABAQUS/Explicit finite element code. The incidence angle was varied as 0°, 15°, 30°, 45°, 57° and 59°. The material parameters for the JC model proposed by the Authors were employed to predict the material behavior of the target, while the material behavior of the projectile was incorporated from the available literature. The numerical results thus obtained have been compared with the experiments reported in earlier study, wherein the incidence velocities of the projectile were considered close to 820 m/s. The experimental and numerical results with respect to failure mechanism, residual projectile velocity and critical angle of ricochet have been compared. A close correlation between the experimental findings and the predicted results has been found. In general, the resistance of the target has been found to increase with increase in target obliquity.
Theoretical and Applied Fracture Mechanics, 2012
The influence of projectile shape and angle of incidence has been studied on the ballistic limit, failure mechanism and angle of ricochet. The Weldox 460 E steel target of 12 mm thickness was subjected to impact by steel projectiles of 20 mm diameter and six different internal nose-angles, namely 33.4°, 60°, 90°, 120°, 150°and 180°. The angle of incidence of the projectiles was also varied as 0°, 15°, 30°, 45°and 60°or until the ricochet of the projectile occurred. The ballistic limit, angle of ricochet and failure mode of the target was studied corresponding to each angle of incidence and projectile shape. The residual velocities for each projectile were also computed using available analytical expressions and the same were compared with their numerical values. The results thus obtained are presented and influence thereon due to the variation in the nose-angle and obliquity of impact are discussed. The ballistic limit was found to increase with an increase in the angle of target obliquity and decrease in projectile nose angle.
International Journal of Impact Engineering, 2020
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The Influence of Single and Double Steel Plate Hardness on Fracture Behavior after Ballistic Impact
Periodica Polytechnica Mechanical Engineering, 2020
This study aims to determine the ballistic characteristics of the two steel plates with different hardness levels and mix in the form of layered in non-permanent constructions. Ballistic testing by caliber 5.56 × 45 mm deformed full metal jacket on a sample plate with each a thickness of 6 mm at a distance of 15 m with a normal angle of attack. The results of ballistic testing on both single plates are they can be pierced by a projectile. While for the layered plate, projectile can only penetrate the front side of the plate. The characteristic of each hole that is formed shows the difference caused by the level of hardness of the plate. On the rear part of the plate, a bulge appears because of an impact from the front side of the plate. In the Soft Plate appear high petals around the hole on the front side with the microstructure deformed on the crater walls. While the hard plate forms small petals on the back side and slightly deformed crater walls. The Soft plate is perforated due...
International Journal of Impact Engineering, 2009
Thin plates of high-strength steel are frequently being used both in civil and military ballistic protection systems. The choice of alloy is then a function of application, ballistic performance, weight and price. In this study the perforation resistance of five different high-strength steels has been determined and compared against each other. The considered alloys are Weldox 500E, Weldox 700E, Hardox 400, Domex Protect 500 and Armox 560T. The yield stress for Armox 560T is about three times the yield stress for Weldox 500E, while the opposite yields for the ductility. To certify the perforation resistance of the various targets, two different ballistic protection classes according to the European norm EN1063 have been considered. These are BR6 (7.62 mm Ball ammunition) and BR7 (7.62 mm AP ammunition), where the impact velocity of the bullet is about 830 m/s in both. Perforation tests have been carried out using adjusted ammunition to determine the ballistic limit of the various steels. In the tests, a target thickness of 6 mm and 6 þ 6 ¼ 12 mm was used for protection class BR6 and BR7, respectively. A material test programme was conducted for all steels to calibrate a modified Johnson-Cook constitutive relation and the Cockcroft-Latham fracture criterion, while material data for the bullets mainly were taken from the literature. Finally, results from 2D non-linear FE simulations with detailed models of the bullets are presented and the different findings are compared against each other. As will be shown, good agreement between the FE simulations and experimental data for the AP bullets is in general obtained, while it was difficult to get reliable FE results using the Lagrangian formulation of LS-DYNA for the soft core Ball bullet.
THE BALLISTIC PROPERTIES OF TOOL STEEL AS A POTENTIAL IMPROVISED ARMOUR PLATE
The ballistic behaviour of a 0.95 weight per cent carbon tool steel against 7.62 mm ball and armour piercing bullets was investigated in the unwelded and welded condition. Gross cracking occurred at plate hardnesses of 510 HV and greater. The mode of perforation for tool steel of hardness 380 HV, which was petalling for 5 mm thick plates and ductile hole formation, followed by discing, for l0 mm thick plates, was similar to that of conventional armour plates of comparable hardness. The ballistic limit increased more with plate hardness for the deforming ball projectile than for the non-deforming armour piercing round. For the latter the ballistic limit was similar to that for rolled homogeneous armour of similar hardness. All welded assemblies suffered from heat affected zones with hardnesses greater than 500 HV, and for the thinner plates, there was hydrogen-induced cold cracking which split the plate before ballistic testing could be completed. Thus an improvised armour could be made from a commercial tool steel, provided the hardness was kept to 380 HV and below and that there were no welds in the assembly. Better improvised armours could be created from other commercial low alloy steel plate of lower carbon content, heat treated to 380 HV, where the welding would be more easily carried out. Welding would be best performed using austenitic electrodes and pre-heating of the plate, with a double V-butt weld configuration to reduce macroscopic distortion. (q',
Ife Journal of Technology, 2016
An experimental analysis of SAN-armour steel plate subjected to high velocity impact of 0.30 calibre armour piercing projectiles is presented. The hardness and impact strength of the plate were assessed following standard procedures; while microstructural examination was carried out on etched sample of the plate. The ballistic performance of the 6 mm thick steel was examined, to obtain an estimate for the V50 ballistic test for armour steel plate, impacting projectiles at 30° obliquity to the target plate from 20 m range. The observed performance was compared with the requirements ofMIL-STD-46100E standards. The results showed that the specimen tested has a tensile strength of 1290MPa, hardness value of 483HBN, 10.1% elongation, impact resistance value of 27J, and that the morphology of the original microstructure has martensitic/bainitic matrix. The ballistic performance of the plate agreed with the minimum ballistic requirements of MIL-STD- 46100E standards. This study, therefore established that the SAN armour steel plate is effective for anti-ballistic applications